Screen for paper-stock.



F. DU M. FOWLER, 'SGRBEN FOR PAPER STOCK. APPLIOATIOK FILED AUG. 6,1910.

Patented Oct. 25, 1910.

INVENTORIH ATTORNEYS WlTNESSES:

0., WASHINGTON, D. c.

P. DU M. FOWLER.

SCREEN FOR PAPER STOCK.

APPLIOATION TILED we. 6, 1910.

Patented Oct. 25, 1910.

2 SHEETEr-SHEET 2.

WITNESSES: INVENTOR;

Y7/Z4 49. \fwz W 7%; Z BY t ATTORNEYS UNITED STATES PATENT OFFICE FREDDU MONT FOWLER, 0F GLENS FALLS, NEW YORK, ASSIGNOR TO INTERNATIONALPAPER COMPANY, OF NEW YORK, N. Y., A CORPORATION OF NEW JERSEY.

SCREEN non PAPER-STOCK.

Specification of Letters Patent Patented Oct. 25, 1910.

Application filed August 6, 1910. Serial No. 575,876.

To all whom it may concern:

Be it known that I, FRED D. FOWLER, a citizen of the United States,residing at Glens Falls, Warren county, State of New York, have inventedcertain new and useful Improvements in Screens for Paper- Stock; and Ido hereby declare the following to be a full, clear, and exactdescription of the invention, such as will enable others skilled in theart to which it appertains to make and use the same.

My invention relates to certain new and useful improvements in apparatusfor screening paper pulp; and particularly to improvements in that typeof such apparatus wherein the screen plates form a series ofsubstantially vertical screen compartments projecting upwardly from thebot tom of the screen into the body of the pulp, and within whichreciprocate a like series 7 of suction pistons.

In the accompanying drawing, Figure 1. represents, partly inlongitudinal section and partly in elevation, a fragmentary view of apulp screen embodying my improvements; Fig. 2. represents, in sideelevation, my preferred form of screen piston, constituting the maincharacteristic feature of my invention; Fig. 3 represents a longitudinalsectional view of the piston and its operating connections; and Fig. 1.represents, on a somewhat larger scale a section taken on a planeindicated by the line 4-4c of Fig. 2.

Similar letters of reference indicate similar parts throughout theseveral views.

Referring to the drawings, A indicates the main body portion orreceiving vat of the screen, adapted to be supplied with the stock to bescreened, from any suitable source, in the continuous manner familiar tothe art, and with the maintenance of the desired head appropriate to theconditions of use. A typical form of screen to which my invention isapplicable is illustrated, for instance, in the U. S. Patent to J. W.Reynolds No. 9417 ,125 dated January 18, 1910. My improvements areconcerned only with the screening parts per se of apparatus of thegeneral type of which the Reynolds screen and others of its kind areparticular examples.

Extending upwardly in the screen vat A are a number of screeningcompartments. The sides a of these screening compartments are made up ofthe usual screen plates for paper stock, these plates being preferablysomewhat inclined toward each other, as indicated in Fig. 1. At theirlower edges, the screen plates may conveniently be set in suitablerecesses of metal retaining strips I), which strips may further besecured in place by means of wood lagging c secured to the wooden bottomd of the screen vat. The bottom (1 is provided with suitable apertures 6extending from end to end of the several screen compartments, puttingthe interior of the screen compartment in communication with the chamberf for the screened stock, said chamber leading the screened stock off tothe usual overflow weir (not shown). At their upper ends, the screens aare spaced apart and united by any suitable cap piece 9.

Within each of the screened compart ments reciprocates a pistonconstructed in accordance with my invention, and each of these pistonsis provided with a piston rod 7L, passing through a guide tube h andstufiing box 2'. Adjacent piston rods are connected by a cross head j,link is, and cocentric boX Z, with a shaft B, mounted in suitablebearings in the frame C of the screen, and driven by a power pulley D,or the like, from any suitable source of power. The revolution of theshaft B, through the connections described, imparts a series of rapidreciprocations to the pistons within the screen compartments.

As shown more fully in Figs. 2, 3, and 4c,

the piston, in the specific form therein illustrated, is provided with abottom m having a number of apertures m, of such dimensions as to permitof the free discharge from the interior of the piston of any screenedstock which enters it in the operation of the screen. The bottom at issecured to the piston rod h by a nut h engaging the upper screw threadedend of the piston rod; and, in order to disassemble the piston from thepiston rod, when desired, a slot k is provided in one of the sides ofthe piston, for the insertion of a suitable spanner wrench, to back offthe nut 7212.

At each end, the piston is provided with an end plate a, and the sidesof the piston are formed, in my preferred practice, from a sheet ofcopper, or the like, bent upon itself, and secured to the end plates 1?.by means of metal straps a and suitable woodscrews, or the like. Eachside ;0 is provided with a series of slots, which are formed by makingcorresponding slits in the metal and swaging the metal out from theplane of the copper sheet, thereby forming corresponding vertical rowsof overlapping strips 1" with the intervening slots 8.

The dimensions of the parts are such that at the complete end of the upstroke of the piston the iron straps a will fall just short of the undersurface of the caps g, and, as shown fully in Fig. 4 these straps willprotect the projecting strips r from coming in contact with the screenplates a. It will also be noted that along the base of each of the sidesof the piston is aflixed a wooden strip 5, these two strips serving tosubstantially fill out the space between the base of the piston and theinner surfaces of the apertures e.

The mode of operation of the screening devices will be apparent, fromthe foregoing description, to those skilled in the art. The rotation ofthe shaft, as has been said, causes the pistons to reciprocate rapidlywithin the screen compartments. The characteristic function of thepistons made in accordance with my invention is that they give apositive blowing action on the Lip-stroke, and a positive screening orsuction action on the down-stroke. Consequently, at every upstroke theslits of the screen plates are cleared of slivers, and, on theclown-stroke, the full suction action is obtained. In practice, it isfound that the screening capacity of the screen is very considerablyincreased by reason of its duplex effect, that the screen can be startedinto action much more promptly than is customary, and that it willmaintain its suction or prime even though the stock should temporarilyfall in the vat to a considerable distance below the top of the screenplates.

Having thus described my invention, what I claim is:

1. Apparatus for screening paper stock, provided with a series ofupright screen compartments, in combination with a series of pistonsreciprocating in said compartments, said pistons having a hollowinterior and slotted walls; substantially as described.

2. Apparatus for screening paper stock, provided with a series ofupright screen compartments, in combination with a series of pistonsreciprocating in said compartments,

said pistons having a hollow interior, and having side walls providedwith a series of slots separated from each other by overlappingprojections; substantially as described.

3. Apparatus for screening paper stock, provided with a series ofupright screen compartments, in combination with a series of pistonsreciprocating in said compartment, said pistons having a hollowinterior, and having side walls provided with a series of slotsseparated from each other by overlapping projections, and having endstraps of such dimensions as to protect said projections from coming incontact with the walls of the screen compartment; substantially asdescribed.

at. Apparatus for screening paper stock, provided with a series ofupright screen compartments, in combination with a series of pistonsreciprocating in said compartments, said pistons having a hollowinterior, and having slotted side walls, and having a bottom plateprovided with discharge apertures; substantially as described.

5. Apparatus for screening paper stock, provided with a series ofupright screen compartments, in combination with a series of pistonsreciprocating in said compartment, said pistons being provided with projections for giving a positive blowing action on the up-stroke and havinga hollow interior for insuring a positive suction on the down-stroke,the pistons being of such dimensions as to substantially fill theinterior of the compartments at the termination of the up-stroke;substantially as described.

6. In apparatus for screening paper stock, a suction piston having ahollow interior and having sheet metal sides provided with a series ofoutwardly swaged slots leaving intermediate inclines one above theother; substantially as described.

7. In apparatus for screening paper stock, a suction piston having ahollow interior and an apertured bottom and having sides provided with aseries of slots having intermediate inclines one above the other;substantially as described.

In testimony whereof I aiiix my signature, in presence of two witnesses.

FRED DU MONT FOlVLER. Witn esses J. GILBERT CooL, C. V. Coor.

